University Communications

Dates and Time


Dates in text

Do not use st, nd, rd, or th following numerals in dates (i.e., April 1, not April 1st).

Days of the week

  • Avoid abbreviation, except when needed in a tabular form.
  • When you must abbreviate, use three letters with no periods (i.e., Sun, Mon, Tue, Wed, Thu, Fri, Sat).

Months of the year

  • Do not abbreviate.
  • When a phrase lists only a month and a year, do not separate the year with commas (e.g., March 1998 was a cold month.  March 17 was a cold day of the month. March 5, 2009, is my wedding date.).


Lowercase spring, summer, fall, winter, and derivatives such as springtime, unless part of a formal name (e.g., The dance will occur in the spring, but Saint Peter’s Spring Fever is coming soon.)


  • Decades are either spelled out and lowercased or expressed in numerals with no apostrophe between the year and the s (e.g., the nineties, the 1990s).
  • You can abbreviate the year by replacing the first two digits with an apostrophe (e.g., the ’90s).  If a font naturally curves the apostrophe, it must open to the left.


  • Spell out centuries (e.g., the twenty-first century).
  • Hyphenate when used as an adjective (e.g., twenty-first-century literature).


Minutes should always follow the hour, and time should always be written in the 11:00 a.m. format.

a.m., p.m.

  • Always lowercase and use periods.
  • Avoid redundancies.
    • Never use 12:00 a.m. or p.m. when using noon or midnight.
    • Do not combine a.m. with in the morning, etc. (e.g., Meet me at 2:00 p.m., not Meet me at 2:00 p.m. this afternoon.).
    • 10 – 11:00 a.m. is preferred rather than 10:00 a.m. – 11:00 a.m.


Avoid describing an event as annual until it has been held at least two successive years.  You may note that sponsors plan to hold the event annually.

Biannual means twice a year or once every six months.

Biennial means every two years.

Bimonthly means every other month.

Semimonthly means twice a month.

Biweekly means every other week.

Semiweekly means twice a week.